Supervisory signal apparatus for telephone-switchboards.



PA'TENTBD'APR. 26, 1904 -E. H. SMYTHE. SUPERVISORY SIGNAL APPARATUS FOR. TELEPHONE SWII'GHBOABDS.

APPLICATION FILED EIT, 14, 1903.

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Patented April 26:1904.

EDIVIN H. SMYTHE, OF FREEPORT, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS,

ILLINOIS.

A CORPORATION OF SUPERVISORY SIGNAL APPARATUS FOR TELEPHONE-SWITCHBOARDS.

SPECIFICATION forming part of Letters Patent No. 758,116, dated April 26, 1904.

Application filed September 14, 1903- Serial No. 173,088. (Ila model.)

To all whom it may concern:

Be it known that I, EDWIN H. SMYTHE, a citizen of the United States, residing at Freeport, in the county of Stephenson and State of Illinois, have invented a certain new and useful Improvement in Supervisory Signal Apparatus for Telephone-Switchboards, of

which the following is a full, clear, concise,

, and exact description.

I My invention relates to supervisory apparatus for telephone-switchboards, and has for its object to provide a system of distinctive signals which will prevent confusion on the part of the central-oflice operator in mak ing connections and disconnections of subscribers lines.

As is well known in systems of the centralized battery type now in common use, when two lines are connected together at the switchboard the supervisory lamp -signal temporarily associated with the called line is displayed at different times during the connection to indicate certain acts to be performed by the central-oflice operatorthat is to say, when the calling-plug is inserted in the spring-jack of the line of a subscriber wanted the supervisory lamp temporarily associated with the line 'is displayed and the operator applies ringing-current to the line as long as the said supervisory signal remains displayed that is, until the called subscriber removes his telephone-receiver from its switch-hook-tnd when the conversation is finished and the subscriber replaces histelephone upon its hook the supervisory lamp is again lighted to indicate a call for disconnection. It often happens, also, that a subscriber immediately upon the completion of one conversation desires to communicate with some other subscriber belonging to the exchange and takes his telephone from its switchhook before the operator'has taken down the connection, whereupon the supervisory signal is again rendered inert, and in order to attract the operators attention the subscriber is compelled to move his switch-hook up and down, causing a flashing of the supervisory lamp.

My aim has been to provide an improved organization of circuits and apparatus for 5 automatically causing the display of characteristic and distinct signals to indicate to the operator the different conditions above described.

My invention will be described particularly 5 5 by reference to the accompanying drawing, which is a diagram illustrating a telephoneline extending from a substation to a central oflice, together with an operators calling-plug and the portion of the plug-circuit associated therewith, the same being organized and Y equipped in accordance with my invention.

The telephone-line shown extends in two limbs 1 2 from the usual substation apparatus A to the poles of a grounded battery 6 at the central ofiice. The line is provided at the central office with spring-jacks a on the several sections of the multiple switchboard. The short and long line springs a a of the spring-jacks a are connected to the line conductors 1 2,1'espeotively, while the thimbles or test-rings c of said spring-jacks form the terminals of a conductor 3, extending to earth through the Winding of a cut-off relay 0. The usual line-signal apparatus is provided for the line, controlled at the back contacts of said cut-01f relay.

I have illustrated diagrammatically the apparatus and circuits associated with the calling-plug of a pair, The central battery 6 is connected in a bridge of said plug-circuit between the windings of a repeating-coil in'the usual manner, and link conductors t 5 extend from the poles of said battery to the" tip and ring contacts cZ (Z respectively, of the calling- 8 5 plug d. A supervisory relay 6 is included in "the linkconductor 5, said relay being responsive to the telephone-switch of a line with which plug (2 may be connected.

When connection is made with any line by 9 inserting the connecting-plug into the springjack thereof, a local circuit 6 3 through the subscribers cut-off relay is closed in registering contacts 623 a of the plug and spring-jack in the well-known manner. A supervisory signal f, which is preferably a small incandescent lamp, is included in the portion 6 of this local circuit which is associated with the connecting-plug. This conductor 6' also incl udes the winding of a relay g. The relay 9, however, is normally shortcircuited by a branch 7 8, controlled at back contacts of its pwn armature and that of the supervisory re- The supervisory relay 6 is adapted when initially excited, as upon the response of the called party, to close a shunt 7 1O 14: about the supervisory signal-lampf. A normally open alternative branch 12 of the shunt is adapted to be substituted for the branch 14 by a relay i. Said branch 12 contains a commutator m, which is adapted intermittently to interrupt said shunt, so that when the shunt is closed through said branch 12 the lamp is caused to give intermittent flashes. Another commutator, 0, constructed to give'more rapidinterruptions than the commutator m, is included in a second branch 9, which is arranged to be brought under the control of the supervisory relay by the excitement of the relay When the supervisory relay allows its armature to fall back after the initial excitation, the shunt 9 8 7 is closed, bringing the commutator 0 into operative relation to the signallamp to cause said lamp to give rapid flashes The magnet of relay 2' is provided with a winding c" included in the conductor 9, so that said magnet z is not excited until the shunt 9 8 7 is closed. This shunt in turn is not closed until the supervisory relay has allowed its armature to fall back after the initial excitation. A high-resistance retaining-winding 11 may be provided for the magnet 7;, controlled in normally closed contacts of the operators listening-key 70, so that when said magnet z'is once excited its armatures will remain held up until the circuit of the retaining-winding is broken by the actuation of the listening-key.

It is understood that the operator is provided with the usual telephone apparatus and with the usual ringing-key by which the substation may be signaled. V

The operation of the system is as follows:

When the connecting-plug is inserted in the spring-jack of a line wanted, the operator actuates her ringing-key in the usual Way to signal the called party, and until the response of the called party the signal-lamp f will be lighted to constitute a ringing-signal, showing that the called party has not responded. As soon, however, as the subscriber removes his telephone from its hook, and so closes the line-circuit, the supervisory relay 6 will be excited in the usual manner by current flowing through the line-circuit and said supervisory relay willclosethe shunt 7 1O 14 about the supervisory lamp, so that said lamp is extinguished. The short circuit 7 8 about the relay g being now open at the back contact of the supervisory relay, said relay g is directly included in the circuit 6 3 and becomes excited, drawing up its armature and extending the circuit of conductor 9 including the interrupter 0 to the back contact of supervisory relay 6, whereby the shunt containing said interrupter 0 is brought under the control of said supervisory relay. Now when the conversation is finished and the subscriber replaces his telephone on its switch, causing the supervisory relay to become inert, the shunt 9 8 7 containing the rapid interrupter 0 will be brought into operative relation to the lamp f, so that said lamp will be caused to rapidly flashl This is the disconnect-signal and'is distinctive from the steady illumination of the lamp, which means, as before stated, that the called party has not yet responded. The flow of current through the shunt 9 excites the relay 2', and the latter once excited holds its armatures up by reason of the retaining-winding 6 before referred to. Relay being excited substitutes the branch 12 for the branch 14, to be controlled at the front contact of the supervisory relay, so that if said supervisory relay is now again excited the lamp instead of being merely shunted out by the conductor 14 will be shunted by the conductor 12 containing the other interrupter, m, whereby said lamp will be caused to flash slowly. If, therefore, after a conversation the subscriber desires to make a recall, he will simply place his telephone on its hook and then take it again. This will cause a complete oscillation of the supervisory-relay ar' mature, whereby the interrupter m will be brought into operative relation to the signal f to cause said signal to give its recall indication. This indication is, as before stated, a slow flashing caused by the interrupter m.

The interrupters m and 0 may be considered as sources of current of distinctive character adapted to produce distinctive indications of the signal, or they may be considered as governing devices for the signal. The relays g and 2', with their armatures and connections, constitute step-by-step switching mechanism controlled by the supervisory relay e,whereby the movements of the armature of said supervisory relay consecutively bring the different governing devices into operative relation to the signal.

Having thus described my invention, I claim 1. The combination with a telephone-line and a substation-switch controlling its circuit, of a central-office relay having an armature responsive to said switch, a supervisory signal, a number of governing devices for said nection-switch for uniting the same with the line, a source of current, a relay in said link conductor having an armature responsive to the substation-switch during connection. asupervisory signal and a circuit therefor, commutators each adapted to modify the current through said supervisory signal to produce indications of distinct character, and step-by-step switching mechanism actuated in the consecutive movements of the supervisoryrelay armature, adapted to bring said commutators one after another into operative re lation to said signal.

3. The combination with a telephone-line and a substation-switch controlling its circuit, of a central-ofiice supervisory relay and means for temporarily associating the. same with the line to respond to said substation-switch, a visual supervisory signal, sources of current of different character adapted to produce distinctive indications of said signal, and stepby-step switching mechanism controlled by.

' the consecutive responses of thesupervisory relay adapted to bring said diiferent sources of current one after another into operative relation to said signal, whereby distinct ringing, disconnect and recall signals are automatically given.

4. The combination with a telephone-line and a substation-switch controlling its circuit, a spring-jack for the line at the central office, a plug and plug-circuit for making connection therewith, a source of current, a relay in said plug-circuit adapted to respond to the substation-switch during connection, a signal, branch circuits in shunt of said signal, current-interrupters in anumber of said branches, and electromagnetic switching -mechanism made active in the closure of one branch for bringing another branch under the control of said supervisory relay.

5. The combination with a telephone-line and its substation-switch, of a central-office connecting-circuit adapted to be temporarily united therewith, means for signaling the substation, a central source of current, a supervisory relay associated with the connecting: circuit and responsive to the substation-switch during a connection, a supervisory signal in a local circuit closed during a connection, a shunt of said supervisory signal, closed by said supervisory relay when excited, a relay g controlled by the initial excitement, of said supervisory relay, and. a second shunt, of different electrical character from the first, brought under the control of the supervisory relay in the response of the said relay 9 and adapted to be closed by said supervisory relay when the same is again inert, whereby the signal is caused to give distinctive indications at different stages in the operation of the system.

connecting-circuit adapted to be temporarily united therewith, means for signaling the substation, a central source of current, a supervisory relay in the connecting-circuit responsive to the substation-switch during connection, asupervisory signal in a local circuit closed during connection, a shunt of said supervisory signal closed at the frontcontact of said supervisory relay when the same is excited, arelay 9 controlled by the initial excitement of said supervisory relay, a second shunt containing an interrupter brought under the control of the back contact of said supervisory relay .in the response of said relay'g, a relay '5 in the last-mentioned shunt, and an alternative branch of the first-mentioned shunt containing a second interrupter, closed by said relay 2' when excited.

*7, The combination with a telephone-line and a substation-switch controlling its circuit, of a supervisory signal, a number of governing devices for said signal, each adapted to produce a distinctive indication thereof, and means controlled through the agency of said substation-switch for consecutively bringing the difierentgoverning devices into operative relation to said signal.

8, The combination with a telephone-line and a substation-switch controlling its circuit, of a link conductor and a central-oilice connection-switch 'for uniting the same with the line, a source of current, a relay in said link conductor having an armature responsive to the substationswitch,a supervisory signal and a circuit therefor, a shunt-circuit of the supervisory signal controlled by said armature, alternative branches of said shunt containing sources of current of different character adapted to produce distinctiveindications of said signal, a relay arranged to close said branches alternatively as it is inert or excited, acircuit for said relay controlled in contacts of the aforesaid armature, a locking-circuit for said last-mentioned relay, an oper ators supervisory key associated with the link conductor, and contacts of the supervisory key controlling said locking-circuit.

9. The combination with a telephone-line and its substation-switch, of a central-office connecting-circuit adapted to be temporarily united therewith, means for signaling the substation, a central source of current, a supervisory relay in the connecting-circuit responsive to the substation-switch during connection, a supervisory signal in a local circuit closed during connection, a shunt of said supervisory signal closed at the front contact of said supervisory relay when the same is excited, a relay g controlled by the initial excitement of said supervisory relay, a second shunt containing an interrupter brought under the control of the back contact of said supervisory relay in the response of said relay g,

a relay e in the last-mentioned shunt, an al- In Witness Whereof I hereunto subscribe my name this 25th day of August, AID. 1903.

EDWVIN H. SMYTHE.

Witnesses:

A. G. TEGMEYER, WM. E. HUBBARD. 

